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Time of flight of projectile motion

  1. Jun 28, 2015 #1
    1. The problem statement, all variables and given/known data
    Why the time of vertical motion and horizontal motion of the projectile are the same ? I couldn't understand it. Could someone explain it ?

    2. Relevant equations


    3. The attempt at a solution
     
  2. jcsd
  3. Jun 28, 2015 #2

    PeroK

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    What do you mean by the time is the same?
     
  4. Jun 28, 2015 #3

    HallsofIvy

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    I agree. You need to tell us what you mean by "time of vertical motion and horizontal motion" being the same. If you fire a projectile at an angle to the horizontal, the time that the projectile takes to reach its maximum height is (neglecting air resistance) the same at it takes to go back down again. That's simply because the vertical acceleration is the same in both directions. The time the projectile takes to "hit the ground" again is NOT the same as the time it takes to reach its maximum height but is the same as the total time to go up and back down. That just an obvious result of what "hit the ground again" means!
     
  5. Jun 28, 2015 #4
    here's what i mean . Part ii
    I couldn't understand why the time of horizontal motion is same as the time
     

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    Last edited: Jun 28, 2015
  6. Jun 28, 2015 #5
    because they are using s as distance, its not the same as units of time s is seconds.
     
  7. Jun 28, 2015 #6

    CWatters

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    Clearly there can only be one time of flight.

    It can't take less or more time to travel horizontally than it did vertically.
     
    Last edited: Jun 28, 2015
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